This invention relates to a disc cartridge and a casing therefor, and more particularly to a casing for a disc cartridge which is adapted to be rotatably and removably house a disc, particularly, a double-sided type hard disc therein and a disc cartridge including such a casing.
In general, a disc-type data recording carrier such as a compact disc (CD), a video disc (LD) or the like is used in a manner such that it is removed from a packing case and set in a recording and/or reproducing equipment such as a disc player.
Conventionally, it has been highly desirable to protect such a disc-type recording carrier from the environment because it is not only easily covered with dust and damaged but adversely affected due to a variation in temperature. For this purpose, a disc cartridge was proposed which is adapted to house or receive a disc in an envelope such as a tray, a casing or the like to accomplish protection of the disc.
Such an envelope for a hard disc typically comprises an upper cover member and a lower cover member fitted together to form an internal space therein in which a sliding member such as a shutter or the like for actuating a window is arranged. The internal space of the envelope is formed to have dimensions sufficient to prevent the disc from being damaged due to contact with an inner surface of the envelope during operation and transportation. For this purpose, a wall thickness of the envelope is substantially decreased, resulting in its torsional rigidity being highly reduced. This causes deformation of the envelope leading to not only damage of the hard disc, but also deterioration of function of the sliding member.
In order to avoid such a disadvantage, such a structure as shown in FIG. 1 was proposed. More particularly, upper and lower cover members 100 constituting an envelope or casing have reinforcing ribs 102 provided on inner surfaces 104 thereof in a symmetric manner. In FIG. 1, only the lower cover member 100 is shown for the sake of brevity. However, such a structure renders removal of a disc from the envelope troublesome, because it is required to release a shutter from the upper and lower cover members and then separate the cover members from each other for the removal.
Another important disadvantage encountered with the structure is that even when reproduction of a disc cartridge is carried out by replacement of a disc or parts of the cartridge, it is often required to dispose the whole disc cartridge due to a failure in precision and/or in view of quality control, resulting in a decrease in yields and deterioration of productivity.
Accordingly, it would be highly desirable to provide a casing for a disc cartridge which is capable of readily and safely accomplishing insertion and removal of a disc with respect to the cartridge without separating a shutter from the casing and/or disassembling the casing and safely housing the disc in the casing without damaging it, and a disc cartridge including such a casing.